Dry develop process of photoresist

ABSTRACT

Embodiments disclosed herein include a method of developing a metal oxo photoresist with a non-wet process. In an embodiment, the method comprises providing a substrate with the metal oxo photoresist into a chamber. In an embodiment, the metal oxo photoresist comprises exposed regions and unexposed regions, and the unexposed regions comprise a higher carbon concentration than the exposed regions. In an embodiment, the method further comprises flowing a gas into the chamber, wherein the gas reacts with the unexposed regions to produce a volatile byproduct.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No.63/047,160, filed on Jul. 1, 2020, the entire contents of which arehereby incorporated by reference herein.

BACKGROUND 1) Field

Embodiments of the present disclosure pertain to the field ofsemiconductor processing and, in particular, to methods of patterning ametal oxo photoresist using a non-wet process.

2) Description of Related Art

Lithography has been used in the semiconductor industry for decades forcreating 2D and 3D patterns in microelectronic devices. The lithographyprocess involves spin-on deposition of a film (photoresist), irradiationof the film with a selected pattern by an energy source (exposure), andremoval (etch) of exposed (positive tone) or non-exposed (negative tone)region of the film by dissolving in a solvent. A bake will be carriedout to drive off remaining solvent.

The photoresist should be a radiation sensitive material and uponirradiation a chemical transformation occurs in the exposed part of thefilm which enables a change in solubility between exposed andnon-exposed regions. Using this solubility change, either exposed ornon-exposed regions of the photoresist is removed (developed). As usedherein, “develop” refers to a process of forming a pattern into thephotoresist. Now the photoresist is developed and the pattern can betransferred to the underlying thin film or substrate by etching. Afterthe pattern is transferred, the residual photoresist is removed andrepeating this process many times can give 2D and 3D structures to beused in microelectronic devices.

Several properties are important in lithography processes. Suchimportant properties include sensitivity, resolution, lower line-edgeroughness (LER), etch resistance, and ability to form thinner layers.When the sensitivity is higher, the energy required to change thesolubility of the as-deposited film is lower. This enables higherefficiency in the lithographic process. Resolution and LER determine hownarrow features can be achieved by the lithographic process. Higher etchresistant materials are required for pattern transferring to form deepstructures. Higher etch resistant materials also enable thinner films.Thinner films increase the efficiency of the lithographic process.

SUMMARY

Embodiments disclosed herein include a method of developing a metal oxophotoresist with a non-wet process. In an embodiment, the methodcomprises providing a substrate with the metal oxo photoresist into achamber. In an embodiment, the metal oxo photoresist comprises exposedregions and unexposed regions, and the unexposed regions comprise ahigher carbon concentration than the exposed regions. In an embodiment,the method further comprises flowing a gas into the chamber, wherein thegas reacts with the unexposed regions to produce a volatile byproduct.

Embodiments may also include a method of developing a metal oxophotoresist that comprises providing a substrate with the metal oxophotoresist on a surface of the substrate, and exposing the metal oxophotoresist to form exposed regions and unexposed regions. In anembodiment, the unexposed regions comprise a higher carbon concentrationthan the exposed regions. In an embodiment, the method may furthercomprise placing the substrate in a plasma chamber, flowing a gas intothe plasma chamber, and striking a plasma in the plasma chamber. In anembodiment, the plasma reacts with the unexposed regions to produce avolatile byproduct. In an embodiment, the method may further comprisepurging the plasma chamber.

Embodiments may also include a method of developing a metal oxophotoresist that comprises providing a substrate with the metal oxophotoresist into a plasma chamber, where the metal oxo photoresistcomprises SnOC. In an embodiment, the metal oxo photoresist comprisesexposed regions and unexposed regions, and the unexposed regionscomprise a higher carbon concentration than the exposed regions. In anembodiment, the method further comprises flowing a gas into the plasmachamber, where the gas comprises Cl₂ and Ar, and striking a plasma inthe plasma chamber. In an embodiment, the plasma reacts with theunexposed regions to produce a volatile byproduct. The method mayfurther comprise purging the plasma chamber.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart describing a process for developing a metal oxophotoresist using a plasma process, in accordance with an embodiment ofthe present disclosure.

FIGS. 2A-2D are cross-sectional illustrations of a substrate and aphotoresist depicting operations in the flowchart of FIG. 1, inaccordance with an embodiment of the present disclosure.

FIG. 3 is a cross-sectional illustration of a processing tool that maybe used to implement portions of the process in FIG. 1, in accordancewith an embodiment of the present disclosure.

FIG. 4 illustrates a block diagram of an exemplary computer system, inaccordance with an embodiment of the present disclosure.

DETAILED DESCRIPTION

Methods of patterning a metal oxo photoresist using non-wet processesare described herein. In the following description, numerous specificdetails are set forth, such as reactive plasma processes and materialregimes for developing photoresist, in order to provide a thoroughunderstanding of embodiments of the present disclosure. It will beapparent to one skilled in the art that embodiments of the presentdisclosure may be practiced without these specific details. In otherinstances, well-known aspects, such as integrated circuit fabrication,are not described in detail in order to not unnecessarily obscureembodiments of the present disclosure. Furthermore, it is to beunderstood that the various embodiments shown in the Figures areillustrative representations and are not necessarily drawn to scale.

To provide context, photoresist systems used in extreme ultraviolet(EUV) lithography suffer from low efficiency. That is, existingphotoresist material systems for EUV lithography require high dosages inorder to provide the needed solubility switch that allows for developingthe photoresist material. Organic-inorganic hybrid materials (e.g.,metal oxo materials systems) have been proposed as a material system forEUV lithography due to the increased sensitivity to EUV radiation. Suchmaterial systems typically comprise a metal (e.g., Sn, Hf, Zr, etc.),oxygen, and carbon. In some instances, the metal oxo material system mayfurther comprise nitrogen and hydrogen. Metal oxo basedorganic-inorganic hybrid materials have also been shown to provide lowerLER and higher resolution, which are required characteristics forforming narrow features.

In a metal oxo photoresist system, exposure to EUV radiation results inthe removal of carbon and the cross-linking of the metal oxide network.The difference in the carbon percentage and bonding strength between theexposed regions and the unexposed regions is used as the solubilityswitch during developing. Particularly, the unexposed regions with thehigher carbon content and weaker bond strength are preferentially etchedby the developer solution.

Metal oxo photoresist systems are currently developed using a wetchemistry. That is, after exposure, the unexposed regions of thephotoresist are developed by organic solvents/base solution that is usedwith a spin-dry process. A post-bake anneal may also be included.However, wet methods can be troublesome when dealing with high aspectratio features due to the risk of pattern collapse (especially in lineor pillar structures). Additionally, wet processes might not remove allof the material that is supposed to be removed and filmmaterials/byproducts/solvents and the like may be trapped in smallfeatures since a mechanical force is used to remove the solvent anddissolved byproducts. Furthermore, with smaller and more complicatedfeatures, it is harder for the solvent (which is usually a largermolecule) to penetrate all areas of the unexposed resist. This leads toa partial develop of the photoresist and causes defects. The spin-dryprocess may also result in line wiggling and even falling off. Thislimits the photoresist thickness and aspect ratio.

Accordingly, embodiments of the present disclosure provide a plasmaetching process to develop metal oxo photoresists. Particularly, plasmaetching processes provide the advantages of: 1) eliminating thegeneration of wet byproducts; 2) lower waste streams due to drychemistry being processed through an abatement system; 3) providingfewer defects and impurities; 4) improvement of LER, LWR, and any lowfrequency roughness originating from surface tension, capillary forces,and spin-dry processes; 5) providing an all-in-one-process fordeveloping a photoresist and transferring the pattern into theunderlayer; and 6) providing a high etch selectivity of the unexposedregions to the exposed regions of the metal oxo photoresist.

Embodiments disclosed herein provide a plasma etching process that isexecuted after portions of a metal oxo photoresist are exposed with asuitable electromagnetic radiation source (e.g., an EUV source). In anembodiment, a substrate comprising an exposed metal oxo photoresist isplaced in a plasma chamber. A gas comprising a reactive gas and an inertgas is flown into the plasma chamber, and a plasma is struck. Thereactive gas is a gas with constituents that react with the metal of themetal oxo photoresist to form a volatile species. For example, thereactive gas comprises one or more of Cl₂, H₂, Br₂, HBr, HCl, BCl₃,CH_(x)Cl_(y), CH₄, BBr₃, and CH_(x)Br_(y). In a particular embodiment,the reactive gas comprises HBr and the inert gas comprises Ar. In someembodiments, the gas is flown into a chamber without striking a plasma(i.e., a thermal process). In other embodiments, a plasma may be struck.In an embodiment, an etch selectivity of the unexposed metal oxophotoresist to the exposed metal oxo photoresist may be 10:1 or greater.In a particular embodiment, the etch selectivity is approximately 12:1.In an embodiment, the pattern of the developed metal oxo photoresist maybe transferred into the underlayer without removing the substrate fromthe plasma chamber.

Referring now to FIG. 1, a flowchart illustrating a process 120 fordeveloping a metal oxo photoresist on a substrate surface is provided,in accordance with an embodiment of the present disclosure. FIGS. 2A-2Dare cross-sectional illustrations of a substrate 261 and a metal oxophotoresist 262 after various operations in process 120.

In an embodiment, process 120 may begin with operation 121 whichcomprises providing a substrate with a metal oxo photoresist. FIG. 2A isa cross-sectional illustration of a substrate 261 with a metal oxophotoresist 262 disposed over a surface of the substrate 261. In anembodiment, the substrate 261 may comprise any substrate material ormaterials typical of semiconductor manufacturing environments. Forexample, the substrate 261 may comprise a semiconducting material.Substrate 261 may comprise semiconductor devices or portions ofsemiconductor devices. Examples of such semiconductor devices include,but are not limited to, memory devices or complimentarymetal-oxide-semiconductor (CMOS) transistors fabricated in a siliconsubstrate and encased in a dielectric layer. The substrate 261 may alsocomprise a plurality of metal interconnects formed above the devices ortransistors, and in surrounding dielectric layers, and may be used toelectrically couple the devices or transistors to form integratedcircuits. In an embodiment, the substrate 261 may be a wafer.

In an embodiment, the metal oxo photoresist 262 (also referred to simplyas “photoresist 262”), may be any metal oxo material system. Suchmaterial systems typically comprise a metal (e.g., Sn, Hf, Zr, etc.),oxygen, and carbon. In a particular embodiment, the photoresist 262,comprises SnOC. In addition to SnOC, embodiments may comprise a metaloxo material system that further comprises nitrogen and hydrogen.

The photoresist 262 may be disposed over the surface of the substrate261 using any suitable deposition process. In an embodiment, thephotoresist is disposed on the surface of the substrate 261 with a wetchemistry using a spin-on process. In an alternative embodiment, thephotoresist is disposed on the surface of the substrate 261 using avapor phase process (i.e., a dry process). In a vapor phase process, ametal precursor and an oxidant may be vaporized to a vacuum chamber,with the metal precursor and the oxidant reacting to deposit a metal oxophotoresist 262 on the surface of the substrate 261. Such dry processesmay be characterized as a chemical vapor deposition (CVD) process, anatomic layer deposition (ALD) process, a plasma enhanced CVD (PE-CVD)process, or a plasma enhanced ALD (PE-ALD) process.

In an embodiment, process 120 may continue with operation 122 whichcomprises exposing portions of the metal oxo photoresist to createexposed regions and unexposed regions. FIG. 2B is a cross-sectionalillustration depicting the exposure process. As shown, electromagneticradiation 264 passes through a mask 263 to expose the exposed regions262 _(E). The unexposed regions 262 _(U) are blocked from theelectromagnetic radiation by the mask 263. In an embodiment, theelectromagnetic radiation is EUV radiation. When EUV radiation is used,the EUV radiation 264 may be reflected off the mask instead of passingthrough the mask. While EUV radiation is specifically disclosed herein,it is to be appreciated that any suitable wavelength of electromagneticradiation that can initiate a solubility switch in the metal oxophotoresist 262 may be used. For example, DUV radiation may be used insome embodiments.

In an embodiment, the solubility switch is provided by the loss ofcarbon and cross-linking of the metal oxo network in the exposedregions. Particularly, the exposure to electromagnetic radiation resultsin the removal of carbon from the exposed regions 262 _(E). The higherthe carbon content and more of the weaker bonds in the unexposed regions262 _(U) renders the unexposed regions more susceptible to patterning inthe subsequent non-wet development process.

In an embodiment, process 120 may continue with operation 123 whichcomprises placing the substrate into a plasma chamber. In an embodiment,the plasma chamber may be any suitable chamber for striking a plasma insub-atmospheric pressure conditions. The plasma chamber may also includeheating/cooling features to provide thermal control of the plasmaprocess. For example, a chuck on which the substrate 261 is placed maybe an actively heated and/or cooled chuck. Additionally, walls of theplasma chamber may be actively heated and/or cooled in some embodiments.A more detailed description of a suitable plasma chamber is providedbelow with respect to FIG. 7.

In an embodiment, process 120 may continue with operations 124 and 125which comprise flowing a gas into the plasma chamber and striking aplasma in the plasma chamber. In an embodiment, the gas comprises areactive gas and an inert gas. The reactive gas may comprise one or moreof Cl₂, Br₂ HBr. HCl, H₂, BCl₃, CH_(x)Cl_(y), CH₄, BBr₃, andCH_(x)Br_(y). In an embodiment, the inert gas may comprise Ar, N₂, orHe. In a particular embodiment, the reactive gas comprises HBr and theinert gas comprises Ar. In an embodiment, the plasma formed by thereactive gas reacts with the unexposed regions of the metal oxophotoresist 262 _(U) to form a volatile byproduct. For example, metal M(e.g., Sn) and Cl will react to form volatile MCl₄. An example of adeveloped photoresist after conversion of the unexposed regions 262 _(U)into a volatile byproduct is shown in FIG. 2C. It is to be appreciatedthat striking a plasma is optional. That is, in some embodiments, anon-wet process may comprise flowing the reactive gas into the chamberwithout striking a plasma. Such a process may be considered a thermalprocess as opposed to a plasma process. In such instances, the reactivegas may directly react with the unexposed regions of the metal oxophotoresist 262 _(U) without the need for ionizing the reactive gas.

In an embodiment, a ratio of a flowrate of the inert gas to a flowrateof the reactive gas is between 0:1 and 50:1. For example, a flowrate ofthe inert gas may be 300 sccm and a flowrate of the reactive gas may be50 sccm. A dilute chemistry slows the etch rate and improves etchinguniformity. Uniformity is improved because the inert gas helps touniformly distribute the reactive gas throughout the plasma chamber.Additionally, it has been generally shown that increases in the flowrateof the reactive gas provides an increase in the etching of the unexposedregions 262 _(U) relative to the exposed regions 262 _(E). In anembodiment, the pressure may be between approximately 1 mtorr andapproximately 100 mtorr. In a particular embodiment, the pressure may bebetween approximately 5 mtorr and approximately 20 mtorr. In yet anotherembodiment, the pressure may be between approximately 1 mtorr andapproximately 10 torr.

In an embodiment, the substrate 261 may have a controlled temperatureduring operations 124 and 125. For example, the temperature may varybetween approximately 0° C. and approximately 500° C. In a particularembodiment, the temperature may vary between approximately 50° C. andapproximately 150° C. Generally, lower temperatures (e.g., less than500° C.) are beneficial since the metal oxo photoresist does notthermally decompose at the lower temperatures. In yet anotherembodiment, the temperature may be less than approximately 200° C. Forexample, the temperature may be between approximately 40° C. andapproximately 100° C.

In an embodiment, RF power of the plasma etching process may becontrolled. Generally, a lower RF power may result in improved etchselectivity. In an embodiment, the source power may be betweenapproximately 200 W and approximately 1200 W. In a particularembodiment, the source power may be approximately 400 W. In anembodiment, the bias power may be between approximately OW andapproximately 200 W. In a particular embodiment, the bias power may beapproximately 50 W. It has been shown that increases of the bias powerup to approximately 100 W provides enhanced etching selectivity of theunexposed regions 262 _(U) relative to the exposed regions 262 _(E).

In an embodiment, operation 125 may be implemented with a pulsed bias.The duty cycle of the pulsing may be between 0% and 100%. In aparticular embodiment, the duty cycle is approximately 50%. Such a dutycycle allows time for byproduct removal and provides less ionbombardment. Accordingly, etch selectivity of the unexposed regions 262_(U) relative to the exposed regions 262 _(E) is improved.

In an embodiment, operation 125 may be implemented for any desiredduration of time. Longer periods of time allow for more of the unexposedregions 262 _(U) to be removed. In an embodiment, operation 125 may havea duration between approximately 5 seconds and approximately 120seconds. In a particular embodiment, operations 125 may have a durationof approximately 15 seconds.

By varying various parameters of the plasma development process, such asthose described above, a high etch selectivity of the unexposed regionsof the metal oxo photoresist 262 _(U) to the exposed regions of themetal oxo photoresist 262 _(E) is provided. For example, the etchselectivity may be approximately 10:1 or greater. In a particularembodiment, the etch selectivity may be approximately 12:1. A high etchselectivity provides several benefits. One such benefit is that thethickness of the photoresist may be reduced. This allows for lower dosesof electromagnetic radiation to be used in order to fully develop thephotoresist.

In an embodiment process 120 may continue with operation 126 whichcomprises purging the plasma chamber. Purging the plasma chamber removesthe byproducts from the reaction in operation 125 from the plasmachamber. In an embodiment, a single purge may be implemented after thecompletion of the etching in operation 125. In alternative embodiments,operations 124/125 and 126 may define a cycle comprising a pulse of theetching followed by a purge. In such embodiments, a plurality of cyclesmay be repeated in order to clear the unexposed regions of thephotoresist 262 _(U).

Embodiments disclosed herein provide the additional benefit of beingimplemented in a plasma chamber. This is especially beneficial when thesubsequent patterning of the substrate 261 is executed using a plasmaetch. Particularly, the substrate 261 does not need to be removed fromthe plasma chamber following the photoresist developing process. Thatis, an all-in-one (i.e., all-in-one chamber) solution for patterndevelopment and pattern transfer into the underlayer is provided.

In an embodiment, process 120 may continue with optional operation 127which comprises etching the substrate 261. FIG. 2D is a cross-sectionalillustration of the substrate 261 after the pattern of the exposedregions of the metal oxo photoresist 262 _(E) is transferred into thesubstrate 261. As shown, the pattern transfer may result in theformation of trenches 265 into the substrate 261. In an embodiment, theetching of the substrate 261 may be implemented using a plasma etchingprocess. The plasma etching process may be executed in the same chamberthat is used to develop the metal oxo photoresist.

FIG. 3 is a schematic of a plasma chamber configured to perform a plasmabased development of a metal oxo photoresist, in accordance with anembodiment of the present disclosure. Plasma chamber 300 includes agrounded chamber 305. A substrate 310 is loaded through an opening 315and clamped to a temperature controlled chuck 320.

Process gases, are supplied from gas sources 344 through respective massflow controllers 349 to the interior of the chamber 305. In certainembodiments, a gas distribution plate 335 provides for distribution ofprocess gases 344, such as Cl₂, Br₂, H₂, HCl, HBr, and/or an inert gas.Chamber 305 is evacuated via an exhaust pump 355.

When RF power is applied during processing of a substrate 310, a plasmais formed in chamber processing region over substrate 310. Bias power RFgenerator 325 is coupled to the temperature controlled chuck 320. Biaspower RF generator 325 provides bias power, if desired, to energize theplasma. Bias power RF generator 325 may have a low frequency betweenabout 2 MHz to 60 MHz for example, and in a particular embodiment, is inthe 13.56 MHz band. In certain embodiments, the plasma chamber 300includes a third bias power RF generator 326 at a frequency at about the2 MHz band which is connected to the same RF match 327 as bias power RFgenerator 325. Source power RF generator 330 is coupled through a match(not depicted) to a plasma generating element (e.g., gas distributionplate 335) to provide a source power to energize the plasma. Source RFgenerator 330 may have a frequency between 100 and 180 MHz, for example,and in a particular embodiment, is in the 162 MHz band. Becausesubstrate diameters have progressed over time, from 150 mm, 200 mm, 300mm, etc., it is common in the art to normalize the source and bias powerof a plasma etch system to the substrate area.

The plasma chamber 300 is controlled by controller 370. The controller370 may comprise a CPU 372, a memory 373, and an I/O interface 374. TheCPU 372 may execute processing operations within the plasma chamber 300in accordance with instructions stored in the memory 373. For example,one or more processes such as portions of process 120 described abovemay be executed in the plasma chamber by the controller 370.

FIG. 4 illustrates a diagrammatic representation of a machine in theexemplary form of a computer system 400 within which a set ofinstructions, for causing the machine to perform any one or more of themethodologies described herein, may be executed. In alternativeembodiments, the machine may be connected (e.g., networked) to othermachines in a Local Area Network (LAN), an intranet, an extranet, or theInternet. The machine may operate in the capacity of a server or aclient machine in a client-server network environment, or as a peermachine in a peer-to-peer (or distributed) network environment. Themachine may be a personal computer (PC), a tablet PC, a set-top box(STB), a Personal Digital Assistant (PDA), a cellular telephone, a webappliance, a server, a network router, switch or bridge, or any machinecapable of executing a set of instructions (sequential or otherwise)that specify actions to be taken by that machine. Further, while only asingle machine is illustrated, the term “machine” shall also be taken toinclude any collection of machines (e.g., computers) that individuallyor jointly execute a set (or multiple sets) of instructions to performany one or more of the methodologies described herein.

The exemplary computer system 400 includes a processor 402, a mainmemory 404 (e.g., read-only memory (ROM), flash memory, dynamic randomaccess memory (DRAM) such as synchronous DRAM (SDRAM) or Rambus DRAM(RDRAM), etc.), a static memory 406 (e.g., flash memory, static randomaccess memory (SRAM), MRAM, etc.), and a secondary memory 418 (e.g., adata storage device), which communicate with each other via a bus 430.

Processor 402 represents one or more general-purpose processing devicessuch as a microprocessor, central processing unit, or the like. Moreparticularly, the processor 402 may be a complex instruction setcomputing (CISC) microprocessor, reduced instruction set computing(RISC) microprocessor, very long instruction word (VLIW) microprocessor,processor implementing other instruction sets, or processorsimplementing a combination of instruction sets. Processor 402 may alsobe one or more special-purpose processing devices such as an applicationspecific integrated circuit (ASIC), a field programmable gate array(FPGA), a digital signal processor (DSP), network processor, or thelike. Processor 402 is configured to execute the processing logic 426for performing the operations described herein.

The computer system 400 may further include a network interface device408. The computer system 400 also may include a video display unit 410(e.g., a liquid crystal display (LCD), a light emitting diode display(LED), or a cathode ray tube (CRT)), an alphanumeric input device 412(e.g., a keyboard), a cursor control device 414 (e.g., a mouse), and asignal generation device 416 (e.g., a speaker).

The secondary memory 418 may include a machine-accessible storage medium(or more specifically a computer-readable storage medium) 432 on whichis stored one or more sets of instructions (e.g., software 422)embodying any one or more of the methodologies or functions describedherein. The software 422 may also reside, completely or at leastpartially, within the main memory 404 and/or within the processor 402during execution thereof by the computer system 400, the main memory 404and the processor 402 also constituting machine-readable storage media.The software 422 may further be transmitted or received over a network420 via the network interface device 408.

While the machine-accessible storage medium 432 is shown in an exemplaryembodiment to be a single medium, the term “machine-readable storagemedium” should be taken to include a single medium or multiple media(e.g., a centralized or distributed database, and/or associated cachesand servers) that store the one or more sets of instructions. The term“machine-readable storage medium” shall also be taken to include anymedium that is capable of storing or encoding a set of instructions forexecution by the machine and that cause the machine to perform any oneor more of the methodologies of the present disclosure. The term“machine-readable storage medium” shall accordingly be taken to include,but not be limited to, solid-state memories, and optical and magneticmedia.

In accordance with an embodiment of the present disclosure, amachine-accessible storage medium has instructions stored thereon whichcause a data processing system to perform a method of developing a metaloxo photoresist on a substrate with plasma processes. The methodincludes exposing a metal oxo photoresist to provide exposed andunexposed regions, and placing a substrate with the exposed photoresistinto a plasma chamber. In an embodiment, a gas is flown into the plasmachamber and a plasma is struck. The gas may comprise a reactive gas andan inert gas. In an embodiment, the plasma reacts with the unexposedregions of the photoresist to convert the unexposed regions of thephotoresist into a volatile byproduct that can be purged from the plasmachamber. For example, the reactive gas may comprise one or more of aCl₂, Br₂, HBr, HCl, and H₂.

Thus, methods for forming a developing a metal oxo photoresist usingplasma processes have been disclosed.

What is claimed is:
 1. A method of developing a metal oxo photoresist,comprising: providing a substrate with the metal oxo photoresist into achamber, wherein the metal oxo photoresist comprises exposed regions andunexposed regions, and wherein the unexposed regions comprise a highercarbon concentration than the exposed regions; flowing a gas into thechamber, wherein the gas reacts with the unexposed regions to produce avolatile byproduct.
 2. The method of claim 1, further comprising:striking a plasma in the chamber.
 3. The method of claim 1, wherein thegas comprises a reactive gas comprising one or more of Cl₂, Br₂, H₂,HBr, HCl, BCl₃, CH_(x)Cl_(y), CH₄, BBr₃, and CH_(x)Br_(y).
 4. The methodof claim 3, wherein the gas further comprises an inert gas.
 5. Themethod of claim 4, wherein a ratio of a flowrate of the inert gas to aflowrate of the reactive gas is between 0:1 and 50:1.
 6. The method ofclaim 1, wherein reacting the gas with the unexposed regions isimplemented with a thermal process without a plasma.
 7. The method ofclaim 1, wherein a substrate temperature of the substrate is 200° C. orlower.
 8. The method of claim 1, wherein a source power is 1200 W orlower, and wherein a bias power is 200 W or lower.
 9. The method ofclaim 8, wherein the bias power is pulsed, wherein the pulsing has aduty cycle between 0% and 100%.
 10. The method of claim 1, wherein themetal oxo photoresist comprises SnOC.
 11. The method of claim 1, whereinthe exposed regions comprise a cross-linked metal oxide network, andwherein the unexposed regions comprise a metal oxide cluster.
 12. Amethod of developing a metal oxo photoresist, comprising: providing asubstrate with the metal oxo photoresist on a surface of the substrate;exposing the metal oxo photoresist to form exposed regions and unexposedregions, wherein the unexposed regions comprise a higher carbonconcentration than the exposed regions; placing the substrate in aplasma chamber; flowing a gas into the plasma chamber; striking a plasmain the plasma chamber, wherein the plasma reacts with the unexposedregions to produce a volatile byproduct; and purging the plasma chamber.13. The method of claim 12, wherein the gas comprises a reactive gas andan inert gas, wherein the reactive gas comprises one or more of Cl₂,Br₂, H₂, HBr, HCl, BCl₃, CH_(x)Cl_(y), CH₄, BBr₃, and CH_(x)Br_(y). 14.The method of claim 13, wherein a ratio of a flowrate of the inert gasto a flowrate of the reactive gas is between 0:1 and 50:1.
 15. Themethod of claim 12, further comprising: etching the substrate beforeremoving the substrate from the plasma chamber.
 16. The method of claim12, wherein the metal oxo photoresist comprises SnOC.
 17. The method ofclaim 12, wherein exposing the metal oxo photoresist comprises exposingthe metal oxo photoresist to extreme ultraviolet (EUV) radiation.
 18. Amethod of developing a metal oxo photoresist, comprising: providing asubstrate with the metal oxo photoresist into a plasma chamber, whereinthe metal oxo photoresist comprises SnOC, wherein the metal oxophotoresist comprises exposed regions and unexposed regions, and whereinthe unexposed regions comprise a higher carbon concentration than theexposed regions; flowing a gas into the plasma chamber, wherein the gascomprises Cl₂ and Ar; striking a plasma in the plasma chamber, whereinthe plasma reacts with the unexposed regions to produce a volatilebyproduct; and purging the plasma chamber.
 19. The method of claim 18,wherein an etch selectivity between the unexposed regions and theexposed regions is 10:1 or greater.
 20. The method of claim 18, whereina ratio of a flowrate of the Ar to a flowrate of the Cl₂ is between 0:1and 50:1.